+++
date = "2018-02-11T21:37:32+00:00"
publishdate = "2023-12-29T07:08:55+00:00"
title = "GPU Acceleration on Remote Desktop"
slug = "headless-gpu-remote-acceleration"
author = "Thedro"
tags = ["headless","server","linux"]
type = "posts"
summary =  "Sometimes the solution to some problems are strange. Imagine a headless, remote, linux based desktop setup where users can remote into a graphical environment."
draft =  ""
syntax =  "1"
toc =  ""
updated =  "2020-01-22"
+++

{{< image source="/images/headless-gpu-remote-acceleration.png" >}} A screenshot
of my remote server's desktop {{< /image >}}

Sometimes the solution to a problem is strange. Imagine a headless, remote,
Linux based desktop setup where users can remote into a graphical environment.
The remote desktop works great with the integrated graphics card but once it
switches to discrete graphics it comes to a screeching halt. No graphical
acceleration.

Many discrete graphic cards now enter a low power state if you do not connect a
monitor. This is good for users who care about power efficiency but a pain for
those who implement headless configurations. The common solution to this problem
is to buy a "dummy plug" for your `HDMI` or Display Port to fake a head onto
your headless configuration. It does work.

There is a way of doing this without a dummy plug. It turns out that we can
pretend that we have a display connected by using `xrandr`. First tell the
system to add new resolution {{< sidenote mark="modes." set="left" >}}We can get
a modeline by using the command `cvt 1024 768`.{{< /sidenote>}}

```shell
xrandr --newmode "1366x768p" 72.00 1366 1414 1446 1494 768 771 777 803;
xrandr --newmode "1280x800p" 24.15 1280 1312 1400 1432 800 819 822 841;
xrandr --newmode "1024x768p" 18.71 1024 1056 1120 1152 768 786 789 807;
```

Then add and assign those resolution modes to a port
{{< sidenote mark="type." set="right" >}}We are using a display
port.{{< /sidenote>}}

```shell
xrandr --addmode DisplayPort-0 "1366x768p";
xrandr --addmode DisplayPort-0 "1280x800p";
xrandr --addmode DisplayPort-0 "1024x768p";
```

Finally pick a mode and then force output on the interface.

```shell
xrandr --output DisplayPort-0 --mode "1366x768p";
```

The discrete graphics card comes alive and we get `GPU` acceleration on the
remote. This may not work for all cards, but it has good coverage. For
everything else there is always the "dummy plug".